The invention relates to an aiming or targeting apparatus for locking nails. As is known, locking nails are bone nails which are provided with through cross-bores through which bone screws are passed. As is known the manufacture of bores in a bone for introducing bone screws through the nail cross-bores requires using an aiming or targeting apparatus. A typical targeting device or aiming apparatus is fixedly connected to the end of the bone nail to which the impaction force to drive in the nail is applied. This normally is the proximal end of the nail if it is introduced into the femur. The nail attachment portion of the targeting apparatus is connected to a targeting arm via a portion which mostly is of a U or L-shaped form. The targeting arm has provided therein cross-bores which are oriented with the bores in the locking nail when the nail is connected to the fixing portion of the targeting device in the way described herein. As was mentioned, since the locking nail has a plurality of cross-bores, which also include an oblique through bore for receiving a femoral neck screw, the individual cross-bores are located at different angles. Preferably, the bores in the targeting arm are of a similar shape. Targeting devices are shown in U.S. Pat. Nos. 5,176,681, 5,334,192 and 6,039,739. The teachings of U.S. Pat. No. 5,334,192 are incorporated herein by reference.
When a bore is made in a bone there naturally is only a need for the single associated bore in the targeting arm. A targeting and drilling sleeve-like guide is then passed through the bore in the arm and is advanced up to the bone and is used as an aid through which the first puncture is then made into the bone, after which drilling is done. To prevent the user from unintentionally choosing a wrong bore in the arm it is further known to push a sleeve over the targeting arm. The sleeve contains a cross-bore or pair of cross-holes which is/are oriented to align with a cross-bore in the targeting arm when the sleeve is slid onto the arm. For example, if four different through bores are provided in the targeting arm four sleeves per targeting apparatus are required to be provided. Since a series of targeting arm sleeves are required for a locking nail each associated sleeve needs to be selected and slid onto the targeting arm. The provision of multiple sleeves requires an expenditure which is not insignificant.